Lecture 9 - Integumentary System Flashcards
1
Q
membranes are composed of:
A
epithelium (epidermis), and connective tissues (dermis)
2
Q
what are the 5 major components of the integumentary system (includes skin and accessory structures)
A
- epidermis (skin)
- dermis (skin)
- exocrine glands (accessory)
- hair (accessory)
- nails (accessory)
3
Q
- largest organ system of the body (15% of total body mass)
- ranges in thickness
- most accessible system = best indicator of general health
- responds directly to local influences
these are all characteristics of:
A
skin
4
Q
what are the five major functions of skin?
A
1) acts as a barrier: physical and immunological protection
2) thermoregulation
3) sensation: touch, pressure, vibration, temperature, pain
4) metabolic functions
5) social functions
5
Q
what are the five layers of the epidermis?
A
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale (germinativum)
(Come Lets Get Sun Burnt)
6
Q
what is the basal layer of the epidermis?
A
the stratum germinativum
7
Q
where are merkel cells and melanocytes found?
A
stratum germinivatum
8
Q
stem cells in the stratum germinivatum constantly divide to give rise to new ______ to replace the dead ones that flake off
A
keratinocytes
9
Q
the most abundant epithelial cells in the epidermis and synthesize keratin
A
keratinocytes
10
Q
forms the basal lamina and ensures that the epithelium is firmly attached to the dermis
A
stratum germinativum
11
Q
the least common cell type, but more abundant where skin has no hair
A
merkel (tactile) cells
12
Q
what is the function of Merkel cells?
A
play an important role in touch sensation
13
Q
what is the tactile (merkel) disc?
A
dermal sensory nerve fibre
14
Q
makes up ~8% of epithelial cells - synthesizes melanin pigment
A
melanocytes
15
Q
melanin granules are _____ by keratinocytes - form an “umbrella” over the nucleus to _____
A
phagocytized, protect DNA from UV radiation
16
Q
what determines skin tone?
A
activity of granules produced and how they spread out in keratinocytes
17
Q
what do melanocytes look like?
A
cells with long, slender processes
18
Q
composed of several layers (8-10) of daughter living keratinocytes and Langerhans cells with protein filaments that attach keratinocytes together
A
stratum spinosum
19
Q
what gives the stratum spinosum its spiny appearance?
A
adjecent cell junctions (provides strength)
20
Q
a type of macrophage that originate from bone marrow and migrates to the epidermis
A
Langerhans (dendritic) cells
21
Q
what is the role of Langerhan cells?
A
phagocytic capabilities and play and important role for immune response if pathogens penetrated the superficial layer
22
Q
where are Langerhan cells found?
A
found in the oral cavity, esophagus, anal cavity, and vaginal canal
23
Q
3-5 layers of mature keratinocytes which produce two types of granules, and is associated with a change in cell shape
A
stratum granulosum
24
Q
what are kerahyalin granules?
A
granules produced by keratinocytes in the stratum granulosum which surrounds keratin (important for cornification)
25
what are lamellar granules?
water-resistant glycolipids produced by keratinocytes in the stratum granulosum which stick cells together (waterproofs the skin)
26
the accumulation of keratin from deep to superficial layers as cells mature
keratinization
27
at what layer in the epidermis do cells start to die?
stratum granulosum
28
how are calluses formed?
the accumulation of too many granules in the stratum granulosum due to abrasion
29
layer of the epidermis which is only present in volar/hairless skin (palmer and plantar skin)
stratum lucidum
30
the stratum lucidum has lots of ____ and thickened _____
keratin, plasma membranes
31
true or false: cells in the stratum lucidum retain their nucleus and organelles
false
32
contains multiple (20-30) layers of flattened, dead, interlocking keratinocytes which have no more organelles and are fully keratinized
stratum corneum
33
the most superficial layer of the epidermis
stratum corneum
34
what is dandruff?
clumps of dander stuck together with oil (sebum) from the scalp
35
what is the function of the stratum corneum?
protection against abrasion and microbial invasion
36
how long does it take epidermal cells to go from the stratum basale to the stratum corneum?
30-40 days
37
the interface between the dermis and epidermis
dermal papilla (dermis) and epidermal ridge (epidermis)
38
the peak and valley interface between the dermis and epidermis allows for:
a tight bond between the different layers of skin (resists shearing stresses)
39
in sensitive areas, such as the lips and genitials, the dermal papillae are tall, allowing ____ near the surface
nerve fibres and capillaries
40
the interface between the dermis and epidermis is very developed and unique to each individual in the:
fingertips
41
what are dermal papillae made of?
areolar connective tissue containing nerve endings, and many capillaries
42
what type of tissue is found in the reticular layer of the dermis?
dense irregular connective tissue
43
provides extensibility and elasticity to the skin, found in the reticular layer of the dermis
collagen bundles and elastic fibres
44
skeletal muscles of the face attach here for facial expressions
reticular layer of the dermis
45
collagen fibre bundles align along lines of _____ in the reticular layer of the dermis and form ______
tension, lines of cleavage
46
what is the clinical significance of the lines of cleavage?
surgeons will try to cut parallel to the line of cleavage so wounds close and heal nicely
47
cuts made perpendicular to the lines of cleavage can improperly heal and form large scars known as:
keloids
48
what are stretch marks?
scarring due to internal damage of collagen bundles and stretching of vasculature
49
stabilizes the position of skin relative to the underlying tissues
hypodermis
50
a loose connective tissue that stores fat, pads the body, serves as an energy reservoir, and provides thermal insulation
hypodermis
51
what are the three pigments responsible for skin tone?
- melanin
- hemoglobin
- carotene
52
what is melanin?
pigment from melanocytes in stratum basale
53
what is the purpose of melanin?
protects from UV radiation
54
what are freckles/moles?
accumulations of melanin/ outgrowth of melanocytes
55
albinism is characterized by:
a lack of melanin
56
produces the red pigment in dermal blood vessels
hemoglobin
57
what is carotene?
a yellow/orange pigment in stratum corneum and hypodermis (precursor to vitamin A)
58
true or false: skin tone can be diagnostic in conditions like cyanosis, erythema, jaundice, pallor, and hematoma
true
59
first degree tissue damage to the skin affects the _____, causes mild pain, and _____
epidermis, erythema (skin redness)
60
second degree tissue damage to the skin affects the _____, causes the formation of _____, edema, redness and pain
epidermis and some dermis, blisters
61
third degree tissue damage to the skin affects _____, results in loss of _____, numbness due to _____, and granulation forms, skin grafting may be needed
epidermis, dermis, and hypodermis; function; loss of nerve endings
62
what is the mechanism of secretion for merocrine glands?
normal exocytosis
63
what is the mechanism of secretion for apocrine glands?
apical surface pinched off
64
what is the mechanism of secretion for holocrine glands?
the entire cell is released
65
what are the four types of exocrine cutaneous glands?
1) sweat glands
2) sebaceous glands
3) ceruminous glands
4) mammary glands
66
what is the function of sweat glands?
secrete water and electrolytes
67
what mechanism of secretion is used in sweat glands?
merocrine secretion and apocrine secretion
68
what is the function of sebaceous glands?
secrete oily lipid (sebum) that coats hair and skin surface
69
what mechanism of secretion is used in sebaceous glands?
holocrine secretion
70
what is the function of ceruminous glands?
secretes earwax
71
what mechanism of secretion is used in ceruminous glands?
apocrine secretion
72
what is the function of mammary glands?
secretes breast milk
73
what mechanism of secretion is used in mammary glands?
apocrine secretion
74
found in the external ear canal - traps foreign particles, prevents entrance, reduces risk of bacterial and fungal functions
cerumen
75
specialized for milk production to feed infant - regulated by interaction of sexual and pituitary hormones
mammary glands
76
- secretes regular sweat
- widespread
- tubes secrete directly onto skin surface
- regulates body temp
- controlled by the sympathetic nervous system
- can also be released due to stress, fear, and embarrassment
these are characteristics of:
merocrine sweat glands
77
- secretes odiferous sweat at puberty
- specific to some body regions (axilla, groin, breast areola, facial hair)
- duct opens into a hair follicle
- strongly influenced by sexual hormones
- stimulated during emotional stress and arousal
these are characteristics of:
apocrine sweat glands
78
inhibits bacterial growth - duct open onto hair follicle
sebum
79
keeps hair and skin from becoming dry, brittle, and cracked
sebum
80
secretions of sebaceous glands
sebum
81
what is acne?
inflammation of sebaceous glands (from blockage of ducts and bacterial infection)
82
at the onset of puberty, sebaceous glands increase in _____ and _____ increases in response to _____
size, secretions, sex hormones
83
both hair and nails are composed of:
dead keratinized cells
84
slender filament of keratinized cells that grow from a tube (follicle)
pilus (pili)
85
where is hair found?
covers all body surfaces except for volar skin (hands and feet), lips, nipples, and parts of genitalia
86
what are the four main functions of hair?
- UV protection
- thermal insulation for head
- particle filtration for eyes and nose
- touch sensation for most of body
87
what are the three main parts of the hair follicle?
- shaft
- root
- bulb
88
part of the hair follicle that lies in the epidermis and above the skin
shaft
89
part of the hair follicle that penetrates and anchors the hair to the dermis
root
90
part of the hair follicle that lies deep in the dermis and allows for epithelial cells growth
bulb
91
hair follicles have an _____ and _____ root sheath
epithelial, connective tissue
92
smooth muscle from dermal collagen fibres (at the papillary layer of the dermis) to the root sheath (connects to sympathetic nervous system)
arrector pili
93
what are the three types of hair?
- lanugo (fine hair foetus to birth)
- vellus (most hair on body)
- terminal hair (longer, coarser, and pigmented)
94
the texture of hair can be coarse or fine depending on:
the keratin content (genetically predetermined)
95
hair colour is a result of:
synthesis of melanin by the melanocytes in the hair matrix
96
the shape of the cross-section of a hair influences:
the curl of the hair
97
part of the hair follicle that is made of densely packed elongated keratinized cells
cortex
98
part of the hair follicle that is made of 2-3 layers of "soft" cells or irregular shape with prescence of air
medulla
99
the matrix of the hair follicle
hair papilla
100
part of the hair follicle that is made of single layer of scaly flat cells overlapping one another - coats the hair
cuticle
101
what are the three stages of the hair growth cycle?
- growth (active) stage
- regression stage
- resting stage
102
what percent of hair is in the growth stage at any given time?
85%
103
stem cells from hair matrix multiply and push existing cells superficially, these cells become keratinized and die (2-6 years in scalp)
growth (active) stage
104
cells in the hair matrix stop dividing, preventing further growth - hair follicle atrophies (shrinks: 2-3 weeks)
regression stage
105
metabolic activity is reduced, hair loses its anchorage and falls out after 3 months
resting stage
106
what are finger nails?
clear scale-like modification of epidermis on distal, dorsal surface of fingers and toes
107
grows 1mm per week from nail root
stratum basale - lunula
108
cells are clear, solid, and visible at the nail body
stratum corneum
109
forms the cuticle (band of epidermis)
stratum corneum
110
part of the nail bed that serves to secure the nail
hyponychium
